The effects of trans-Pt(II) and cis-Pt(II) on the biochemical (ultracentrifugation) and biological (transfection of lambda phage DNA) properties of DNA are being studied. With trans-Pt(II) inactivation of lambda phage DNA is directly proportional to the fraction of lambda DNA molecules with an interstrand crosslink. With cis-Pt(II) there are approximately five lethal lessions per interstrand crosslink, indicating that a intrastrand lesion is the major lethal lesion induced by cis-Pt (II). All Pt(II) induced lesions are reversed by thiourea as studied by biological and biochemical assays. Several new methods of histone analysis have been developed. Using these methods, we have discovered and are characterizing two novel variants of histone 2A. We are also characterizing a crosslinked histone dimer found after carbodiimide treatment. The dimer contains H1 and H2A, and is being used to study the relationship of H1 to other histones, and its role in chromosome structure and function.